The ATK Framework is a PHP business framework. It
is targeted at developers who wish to focus on
business logic instead of coding HTML. ATK
provides a complete framework that requires only
small amounts of code to get usable applications,
while maintaining full flexibility. ATK has a
model driven approach, but is 100% customizable.

AbiWord is a free word processing program similar to Microsoft Word. It is suitable for a wide variety of word processing tasks. It allows you to collaborate with multiple people on one document at the same time. It is tightly integrated with the AbiCollab.net Web service, which lets you store documents online, allows easy document sharing with your friends, and performs format conversions on the fly.

Achievo is a Web-based project management and tracking tool for small- to medium-sized companies, aiming to become a fully featured ERP-like system in the future. Features include a time registration module, scheduler, project management, todo's, and several statistical tools. Achievo is multi-language, fully customizable, and uses a modular system to allow future extensions.

The Advanced Bash Scripting Guide is both a reference and a tutorial on shell scripting. This comprehensive book, the equivalent of 1,000+ print pages, covers almost every aspect of shell scripting. It contains 382 profusely commented illustrative examples, a number of tables, and a cross-linked index/glossary. Not just a shell scripting tutorial, this book also provides an introduction to basic programming techniques, such as sorting and recursion. Included scripts are the Game of Life, a Perquackey variant, a Morse code trainer, and an implementation of the Gronsfeld Cipher. This book is suited for both individual study and classroom use. It covers Bash, up to and including version 4.2.
Note that users of miniaturized single-board computers
running Linux, such as the Raspberry Pi and the Beagle
Bone, would find this Guide useful for learning and running Bash scripts to explore and expand the capabilities of these small, but powerful machines.

Aegisub is an advanced subtitle editor that assists in the creation of subtitles, translations, and complex overlays using audio or video. Developed by enthusiasts it builds on workflows created and perfected through professional, hobby, and everyday use.

AeroMail is a Web-based email client that uses an
IMAP server to read and store messages in one or
more user-defined folders. Features include: HTTP
authentication for login (no cookies) or login
with cookies; Optional IMAP folder manipulation;
optional spam flagging using reverse DNS mapping;
HTML messages and attachments; simple HTML that
can be embedded in a page of your own design;
support for different character sets (e.g. Russian
and Chinese); support for SSL IMAP servers; and
support for sendmail's genericstable (reverse
mapping of users for outbound mail). JavaScript is
not necessary.

Airtime lets you take total control of your radio station via the Web with intelligent archive management, powerful search, an easy playlist builder, a simple scheduling calendar, and rock-solid automated playout. Features include fades, cues, playlists, a programme calendar, Icecast, Shoutcast, and Soundcloud integration, DJ and station manager roles, JQuery widgets, Liquidsoap playout, and a record and rebroadcast functionality. Powerful media archive features 'watch' folders to allow stations to magically synchronize files, auto-import files, and has multiple directory support. Users can interact with it through any Web browser. It comes with an 'easy install' package.

Alexandria is a GNOME application to help manage a
book collection. It retrieves book information
(including cover pictures) from several online
libraries, allows you to search for a book (either
by EAN/ISBN, title, authors, or keyword), can
import and export data into ONIX, Tellico, and
EAN/ISBN-list formats, generates Web pages from
your libraries, allows marking your books as
loaned, saves data using the YAML format, features
an HIG-compliant user interface, shows books in
different views that can be filtered or sorted,
and handles book rating and notes.

Another PostgreSQL Diff Tool (also known as apgdiff) is a PostgreSQL diff tool that is useful for schema upgrades. The tool compares two schema dump files and creates an output file that is (after some hand-made modifications) suitable for upgrading an old schema.